Void value as return parameter

Question

I have this interface:

public interface Command {
    T execute(String... args);
}

it works fine for most uses. But when I try to mode

Answer 1

What if instead of having an interface like:

public interface Command {
    T execute(String... args);
}

You instead had:

public interface Command {
    void execute(String... args);
    T getResult();
    bool hasResult();
}

Then callers would do:

public void doSomething(Command cmd) {
    cmd.execute(args);
    if(cmd.hasResult()) {
        // ... do something with cmd.getResult() ...
    }
}

You could also create an interface VoidCommmand that extends Command, if you like.

This seems like the cleanest solution to me.